Before plastic Guitar Picks appeared, the Guitar Picks were made of cuttlebone, metal, wood, amber, stone, ivory or tortoise shell.
Guitarists used to make their own pick, filing these materials to the shape they wanted.
The first plastic Guitar Picks were made in 1922 by a company named D'Andrea Picks. They made it from tortoise shell-like celluloid.
D'Andrea Picks was the first company that created custom pick imprinting. They also set the standard for some of today's famous picks, for example the 351, or 346 the rounded triangle and the 358 the small jazz pick.